BezierDemo源码解析-实现qq消息气泡拖拽消失的效果 - c++编程基础

这篇文章中我们比较了DraggableFlagView和BezierDemo两个项目的区别，提到将对其中一个做源码分析，那么我们就来分析BezierDemo的源码吧，因为这个项目的源码最简单，可以更直接的去分析核心的东西。但是效果还是DraggableFlagView好些。我尽量讲的详细些，满足更多的初学者。这篇文章主要分析拉伸效果的实现。

源码结构

BezierDemo只有两个java文件

QQ图片20150310211436.png

其中MainActivity.java是程序界面，而BezierView.java是实现了粘连拉伸效果的类。

MainActivity.java

package github.chenupt.bezier;

import android.app.Activity;
import android.os.Bundle;


public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }


}

activity_main.xml

这里有个疑问：为啥BezierView控件的layout_width和layout_height为match_parent。这是因为这个代码很粗糙，哈哈。

好了，从上面的activity可以看出，所有的功能都是BezierView控件实现的，因此我们直接转向BezierView.java

先贴代码

package github.chenupt.bezier;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.PorterDuff;
import android.graphics.Rect;
import android.graphics.drawable.AnimationDrawable;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.widget.FrameLayout;
import android.widget.ImageView;

/**
 * Created by chenupt@gmail.com on 11/20/14.
 * Description : custom layout to draw bezier
 */
public class BezierView extends FrameLayout {

    // 默认定点圆半径
    public static final float DEFAULT_RADIUS = 20;

    private Paint paint;
    private Path path;

    // 手势坐标
    float x = 300;
    float y = 300;

    // 锚点坐标
    float anchorX = 200;
    float anchorY = 300;

    // 起点坐标
    float startX = 100;
    float startY = 100;

    // 定点圆半径
    float radius = DEFAULT_RADIUS;

    // 判断动画是否开始
    boolean isAnimStart;
    // 判断是否开始拖动
    boolean isTouch;

    ImageView exploredImageView;
    ImageView tipImageView;

    public BezierView(Context context) {
        super(context);
        init();
    }

    public BezierView(Context context, AttributeSet attrs) {
        super(context, attrs);
        init();
    }

    public BezierView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        init();
    }

    private void init(){
        path = new Path();

        paint = new Paint();
        paint.setAntiAlias(true);
        paint.setStyle(Paint.Style.FILL_AND_STROKE);
        paint.setStrokeWidth(2);
        paint.setColor(Color.RED);

        LayoutParams params = new LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);
        exploredImageView = new ImageView(getContext());
        exploredImageView.setLayoutParams(params);
        exploredImageView.setImageResource(R.drawable.tip_anim);
        exploredImageView.setVisibility(View.INVISIBLE);

        tipImageView = new ImageView(getContext());
        tipImageView.setLayoutParams(params);
        tipImageView.setImageResource(R.drawable.skin_tips_newmessage_ninetynine);

        addView(tipImageView);
        addView(exploredImageView);
    }

    @Override
    protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
        exploredImageView.setX(startX - exploredImageView.getWidth()/2);
        exploredImageView.setY(startY - exploredImageView.getHeight()/2);

        tipImageView.setX(startX - tipImageView.getWidth()/2);
        tipImageView.setY(startY - tipImageView.getHeight()/2);

        super.onLayout(changed, left, top, right, botto

BezierDemo源码解析-实现qq消息气泡拖拽消失的效果(一)

源码结构